An Experimental and Computational Study on the Effects of Ball Milling on the Physicochemical Properties and Digestibility of a Canna Starch/Tea Polyphenol Complex

To investigate the impact of tea polyphenols on the thermodynamic properties, gelatinization properties, rheological properties, and digestion characteristics of starch after ball milling, canna starch and tea polyphenols were mixed at a 10:1 ratio (<i>w</i>/<i>w</i>) in an experiment and processed with different ball milling times. After ball milling for 3 h, the tea polyphenols and starch fragments formed complexes. Compared with the unmilled mixture, the solubility increased by 199.4%; the shear stress decreased by 89.48%; and the storage modulus and loss modulus decreased. The content of resistant starch first decreased and then increased. Infrared results revealed that ball milling led to a non-covalent interaction between the tea polyphenols and starch. Molecular dynamics simulations were used to study the interaction between the starch and tea polyphenols. The binding free energy of the main component, epigallocatechin gallate (EGCG), in tea polyphenols with starch was reduced from -23.20 kcal/mol to -26.73 kcal/mol. This experiment can provide a reference for the development of functional starch with high resistant starch content.